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Effect of 5 years of exercise training on the cardiovascular risk profile of older adults: the Generation 100 randomized trial

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(1)European Heart Journal (2021) 00, 1–12 doi:10.1093/eurheartj/ehab721. CLINICAL RESEARCH Clinical trials. Jon Magne Letnes 1,2,3, Ida Berglund 1, Kristin E. Johnson 1, Håvard Dalen 1,2,3, Bjarne M. Nes 1,2, Stian Lydersen 4, Hallgeir Viken1, Erlend Hassel 5,6, Sigurd Steinshamn 1,6, Elisabeth Kleivhaug Vesterbekkmo 1,2, Asbjørn Støylen 1,2, Line S. Reitlo1, Nina Zisko1, Fredrik H. Bækkerud 1, Atefe R. Tari1, Jan Erik Ingebrigtsen7, Silvana B. Sandbakk1,8, Trude Carlsen1, Sigmund A. Anderssen9, Maria A. Fiatarone Singh10,11, Jeff S. Coombes 12, Jorunn L. Helbostad13, Øivind Rognmo1,2, Ulrik Wisløff1,12, and Dorthe Stensvold1,2* 1. Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Post Box 8905, Trondheim 7491, Norway; 2Department of Cardiology, St Olavs University Hospital, Prinsesse Kristinas gate 3, Trondheim 7030, Norway; 3Levanger Hospital, Nord-Trøndelag Health Trust, Kirkegata 2, Levanger 7600, Norway; 4Regional Centre for Child and Youth Mental Health and Child Welfare, Norwegian University of Science and Technology, Post Box 8905, Trondheim 7491, Norway; 5Norwegian Armed Forces Occupational Health Service, Post Box 800, Lillehammer 2617, Norway; 6Department of Thoracic Medicine, Clinic of Thoracic and Occupational Medicine, St Olavs University Hospital, Prinsesse Kristinas gate 3, Trondheim 7030, Norway; 7Department of Sociology and Political Science, Faculty of Social and Educational Sciences, Norwegian University of Science and Technology, Post Box 8905, Trondheim 7491, Norway; 8Department of Teacher Education, Faculty of Social and Educational Sciences, Norwegian University of Science and Technology, Post Box 8905, Trondheim 7491, Norway; 9Department of Sports Medicine, The Norwegian School of Sport Sciences, Sognsveien 220, Oslo 0863, Norway; 10Sydney School of Health Sciences and Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, NSW 2006, Australia; 11Hinda and Arthur Marcus Institute for Aging Research, Hebrew SeniorLife, 1200 Centre St, Boston, MA 02131, USA; 12School of Human Movement and Nutrition Science, University of Queensland, Human Movement Studies Building, St Lucia QLD, Queensland 4067, Australia; and 13Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Post Box 8905, Trondheim 7491, Norway Received 27 April 2021; revised 9 July 2021; editorial decision 21 September 2021; accepted 1 October 2021. Listen to the audio abstract of this contribution.. Aims. The aim of this study was to compare the effects of 5 years of supervised exercise training (ExComb), and the differential effects of subgroups of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT), with control on the cardiovascular risk profile in older adults.. ................................................................................................................................................................................................... Methods Older adults aged 70–77 years from Trondheim, Norway (n = 1567, 50% women), able to safely perform exercise training were randomized to 5 years of two weekly sessions of HIIT [90% of peak heart rate (HR), n = 400] or MICT (70% of and results peak HR, n = 387), together forming ExComb (n = 787), or control (instructed to follow physical activity recommendations, n = 780). The main outcome was a continuous cardiovascular risk score (CCR), individual cardiovascular risk factors, and peak oxygen uptake (VO2peak). CCR was not significantly lower [-0.19, 99% confidence interval (CI) -0.46 to 0.07] and VO2peak was not significantly higher (0.39 mL/kg/min, 99% CI -0.22 to 1.00) for ExComb vs. control. HIIT showed higher VO2peak (0.76 mL/kg/min, 99% CI 0.02–1.51), but not lower CCR (-0.32, 99% CI -0.64 to 0.01) vs. control. MICT did not show significant differences compared to control or HIIT. Individual risk factors mostly did not show significant between-group differences, with some exceptions for HIIT being better than control. There was no significant effect modification by sex. The number of cardiovascular events was similar across groups. The healthy and fit study sample, and. * Corresponding author. Email: dorthe.stensvold@ntnu.no C The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology. V. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. Effect of 5 years of exercise training on the cardiovascular risk profile of older adults: the Generation 100 randomized trial.

(2) 2. J.M. Letnes et al.. contamination and cross-over between intervention groups, challenged the possibility of detecting between-group differences.. ................................................................................................................................................................................................... Conclusions Five years of supervised exercise training in older adults had little effect on cardiovascular risk profile and did not reduce cardiovascular events.. ................................................................................................................................................................................................... Registration ClinicalTrials.gov: NCT01666340. 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏 䊏. Five years of supervised exercise did not significantly improve the cardiovascular risk profile of older adults compared to a control group advised to follow national recommendations for physical activity. In comparisons between the different exercise intensities there was a signal towards a favourable effect in the high-intensity interval training group for several of the risk factors, but the present study did not show conclusive evidence.. ................................................................................................................................................................................................... Keywords Exercise • High-intensity interval training • Ageing • Cardiovascular risk factors • Cardiorespiratory fitness. Introduction The number of older adults in the world is expected to double between 2015 and 2050.1 Ageing is associated with unfavourable physiological and functional changes, including changes in cardiorespiratory fitness (CRF) measured as peak oxygen uptake (VO2peak),2 adiposity,3 blood pressure (BP),4 and muscle mass,5 all of which contribute to increased risk of cardiovascular disease (CVD). VO2peak is a strong predictor of CVD,6 and a 20% decline in VO2peak over 10 years has previously been observed in older adults.7 Exercise increases VO2peak,8,9 and several studies have indicated that high-intensity interval training (HIIT) gives larger increases when compared to moderate-intensity continuous training (MICT).10,11 Also, HIIT has shown more pronounced effects on CVD risk factors than MICT in other populations at high CVD risk.12 Beneficial adaptations in VO2peak and cardiovascular health have been observed even when. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... becoming physically active at older age,13 and a systematic review of exercise interventions in older adults has indicated positive effects on cardiovascular risk factors.14 However, effects on several CVD risk factors such as BP and lipids are heterogeneous with variable quality of the available evidence.14 Also, the impact of different exercise intensities has not been established, and studies lasting >1 year are rare.10,14 Thus, long-term studies comparing different exercise intensities at similar exercise volumes are needed to be able to give best possible advice regarding physical activity for increasing CRF and reducing CVD risk in older adults. Of note, the current physical activity recommendations do not emphasize performing moderate- or high-intensity exercise over the other, and this needs further investigation. The aim of this study was to assess the effect of 5 years of supervised exercise training (exercise combined; ExComb) on cardiovascular risk profile compared to Norwegian national physical activity recommendations (control) in older adults. Second, we aimed to. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. Graphical Abstract.

(3) 3. Cardiovascular risk profile of older adults. assess differential effects of HIIT and MICT compared to each other and control on these outcomes.. Methods Study population and design This study includes participants from the Generation 100 study that investigated the effects of exercise training on all-cause mortality (ClinicalTrials.gov: NCT01666340) in older adults aged 70–77 years.15 Sample size calculations were performed for the main outcome of mortality. In Trondheim (2010), 2% of the population between 70 and 77 years died, and the expected mortality rate after 5 years would be 10%. With a power of 90%, about 600 participants were needed in each group (ExComb and control) to detect a 50% reduction in mortality (i.e. from 10% to 5%). The study aimed to include 1500 participants to allow for up to 20% of dropouts.15,16 Here, we address pre-specified secondary outcomes including VO2peak and traditional cardiovascular risk factors. All inhabitants in Trondheim municipality in central Norway born between 1936 and 1942 were invited. Exclusion criteria before and during the study are reported in Supplementary material online, Methods. The study was initiated in 2012 and included 1567 participants who were randomized 2:1:1, stratified by sex and cohabitation status, to either a control group (control, n = 780), MICT (n = 387), or HIIT (n = 400). The combination of HIIT and MICT defined the pre-specified ExComb group.. .. The Unit for Applied Clinical Research at the Norwegian University of .. .. Science and Technology (NTNU) performed the randomization to en.. sure impartial allocation. Participants filled in questionnaires and under.. .. went clinical examinations, blood sampling, and physical tests before .. randomization (baseline) and after 1, 3, and 5 years (last follow-up in .. in Figure 1, and a .. 2018). Overview of study16 inclusion and design is shown .. detailed study protocol and the primary outcome15 have been pub.. lished. The study protocol and statistical analysis plan for the Generation .. .. 100 study is available in the Supplementary material online. .. The present study was approved by the Regional Committee for .. .. Medical Research Ethics (REC South East B; REK2012/381B). All study .. participants signed an informed consent form prior to inclusion. ... .. .. Exercise intervention .. The control group was asked to follow the recommendations of the .. .. Norwegian Health Authorities for physical activity (per 2012),17 being .. 30 min of moderate-intensity physical activity most days a week, without .. receiving further supervision. The HIIT group was asked to complete .. .. 40 min of HIIT two times per week, consisting of 4  4 min intervals with .. an intensity 90% of peak heart rate (HR) during intervals, corresponding .. .. to 16 on the Borg scale.18 Based upon the testing of VO2peak as .. described below, we established individual HR-VO2 relationships to cal.. .. culate average energy consumption in an HIIT session, which was then .. used to calculate the volume (minutes) of MICT that was needed to .. match the ‘HIIT-kcal usage’. Based upon these calculations, MICT was. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. Figure 1 Flowchart of participant inclusion and follow-up. The number of participants showing up for repeated examination and testing at each study year is shown in the box below each intervention group. HIIT, high-intensity interval training; MICT, moderate-intensity continuous training..

(4) 4. Cardiopulmonary exercise testing Participants underwent cardiopulmonary exercise testing to voluntary exhaustion on a treadmill (PPS55 Med, Woodway GmbH, Germany), or a bike if physical limitation or balance issues precluded treadmill exercise (Monark cycle ergometer, Monark Exercise AB, Sweden; 3.4% of tests), with continuous gas analysis using the Cortex MetaMax II (Cortex Biophysik Gmbh, Leipzig, Germany) or the Oxycon Pro (Erich Jaeger, Hoechberg, Germany, 3.8% of tests). The same system was used for each participant at all follow-ups, but 43 participants switched between treadmill and cycle ergometer or the other way around during the study due to physical challenges, and for these participants any tests using the cycle ergometer were excluded (n = 54) in analyses for VO2peak. Participants’ regular medications were continued prior to exercise testing and all other measurements. Test personnel were blinded for participants’ intervention arm. The individualized steady-state test protocol started at a speed and inclination set during warm-up guided by the Borg scale. The first stage was held for 3 min, or longer if steady state was not reached. Stage 2 was initiated by increasing the intensity, either by 1 km/h in speed or by 2% inclination (or 10 W if using bike). After completing the second submaximal stage lasting 1.5 min, the intensity increased similarly every minute (or 30 s on bike), or when the values had stabilized, until the participant stopped the test due to exertion, or VO2max was achieved. The protocol lasted 8–12 min as recommended by Froelicher and Myers.22 The same exercise testing protocol and equipment was used at all study. .. years. Further information on testing and calibration procedures has .. .. been described in detail previously.23 The VO2peak was recorded as the .. average of the three highest consecutive measures over 30 s. Maximal .. .. oxygen uptake (VO2max) was defined as achieved if VO2 did not increase .. >2 mL/kg/min the last 30 s before test termination as well achieving a re.. .. spiratory exchange ratio >_1.05. Since 40% of tests did not meet objective .. VO2max criteria, the term VO2peak is used throughout. .. .. .. Clinical and biochemical measurements .. Participants were asked to fast and avoid exercise and alcohol for 12 and .. .. 24 h preceding measurements, respectively, although not before exercise .. testing. Height was measured standing straight against a wall with feet hip.. .. distance apart. Waist circumference was measured above the iliac crest, in .. a standing position with feet hip-distance apart, arms crossed above the .. .. chest, and with relaxed breathing at exhalation. Body mass measurements .. and calculations of fat-free mass [body mass  (1 - (body fat percentage/ .. 100)] were performed on a bioelectrical impedance scale (Inbody 720, .. .. BIOSPACE, Seoul, Korea). Body mass index (BMI) was calculated. After .. resting 5 min in a chair with arms rested, BP was measured twice with a 1.. .. min break from the right upper arm (Philips Medizin Systeme, Boeblingen, .. Germany). If systolic/diastolic BP differed by >_10/6 mmHg between meas.. urements, a third measurement was taken, and the average of the last two .. .. BP recordings was used. The mean arterial pressure (MAP) was calculated .. as diastolic BP þ 1/3  pulse pressure. Blood samples were drawn from .. .. an arm vein by trained personnel using standardized procedures (St. Olavs .. University Hospital). Serum high-density lipoprotein cholesterol (HDL-C) .. .. and total cholesterol (TC), triglycerides (TG), glucose, and glycosylated .. haemoglobin were analysed immediately after sampling. Low-density lipo.. protein cholesterol (LDL-C) was calculated by the Friedewald formula at .. .. baseline and Year 1, directly measured by Roche Modular P at Year 3, and .. by Siemens Advia Chemistry XPT at Year 5. Calculated and directly meas.. .. ured LDL-C have shown good agreement.24 Information on smoking, alco.. hol use, previous medical history, and exercise habits was based on self.. report. Information on prescription medication use was collected from the .. .. Norwegian Prescription Database (Supplementary material online). Data .. on clinical events were gathered as previously described.15 .. .. .. Statistical analyses .. .. Baseline clinical characteristics are presented as mean and SDs or as .. count and percentages, and for the risk factors graphically as means and .. .. 99% Wald confidence intervals (CIs). To assess the combined effect on .. several cardiovascular risk factors, a continuous cardiovascular risk score .. (CCR) was constructed by summarizing sex-specific z-scores for waist .. .. circumference, MAP, the inverse of HDL-C, and the logarithm of TG and .. fasting glucose, similar to variables used in the definition of the metabolic .. .. syndrome.25 Z-scores were calculated by subtracting the mean from the .. given value and dividing by the SD.26 The mean and SD from baseline for .. each variable were used for calculations at all time points, allowing for the .. .. detection of difference in change between the groups.27 Using the same .. variables as a cluster of metabolic syndrome has been shown to signifi.. .. cantly predict CVD in adults and older adults,28,29 but we chose a con.. tinuous score of the same variables instead to reduce information loss .. with other studies assessing cardio.. and power by dichotomization, in line .. vascular risk factors in older adults.27 To assess the between-group treat.. ment effects for the various outcomes, we specified a linear mixed model .. .. adjusting for cohabiting status, sex (variables used in stratified randomiza.. tion), and age at inclusion. Participants were included as random intercept .. .. in the models. Analyses were adjusted for the baseline value based on the .. rationale and method described by Twisk et al.30 Using this method, the .. between-group treatment effects are directly interpretable as the esti.. . mate for the group  time interaction. For each risk factor two separate. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. asked to complete 50 min of continuous exercise training two times per week with an intensity of 70% of peak HR/Borg scale 13. In this way, the only thing that differ between MICT and HIIT was the intensity of the exercise, as we also reported in previous studies.11,12,19 Every sixth week, both groups met separately for supervised spinning sessions (ergometer cycling) with an exercise physiologist, where they exercised with HR monitors to ensure that recommended relative exercise intensities were being achieved. Supervised training with exercise physiologists present was also offered, meaning that these sessions were not mandatory, twice a week in different outdoor areas, although during winter one session was held indoors. Exercise intensity was evaluated by HR monitors and rating of perceived exertion (Borg scale) during the supervised sessions. Although exercise intensity was given by intervention group, exercise mode was self-selected, and most participants preferred walking.20 Data from the HR monitoring showed that, for this age group, uphill walking was effective in reaching 90% of peak HR, in line with findings at baseline testing, where 86% of participants were exercising at a treadmill speed <_6 km/h at peak exercise, which is below the typical walk-run transition.21 For HIIT and MICT, respectively, the mean HR at the supervised exercises was 93% and 77% at Year 1, 90% and 74% at Year 2, 87% and 74% at Year 3, 91% and 72% at Year 4, and 87% and 69% at Year 5 (all HIIT vs. MICT comparisons P < 0.001). In total, the mean HR was 90% in HIIT and 72% in MICT, with rating of perceived exertion of 16.9 and 13.8, respectively. As pre-defined in the protocol article,16 adherence to the prescribed exercise program was defined as having performed at least 50% of the prescribed training sessions over the 5 years. After 1, 3, and 5 years, adherence to prescribed exercise was 50%, 49%, and 47% for HIIT and 63%, 55%, and 51% for MICT. Participant in control had a stable physical activity level throughout the study with 78%, 70%, and 69% meeting recommendations after 1, 3, and 5 years, respectively. Furthermore, there was a cross-over between the interventions, particularly in the control group was 23%, 22%, and 18% for HIIT after 1, 3, and 5 years, with corresponding values of 12%, 14%, and 11% for MICT.15 The mean [standard deviation (SD)] number of weekly exercise sessions at baseline and 5 years was 3.9 (0.9) and 4.0 (0.9) for control, 4.0 (0.8) and 4.1(0.7) for MICT, and 3.9 (0.9) and 4.1 (0.7) for HIIT.. J.M. Letnes et al..

(5) 5. Cardiovascular risk profile of older adults. Results Baseline characteristics are shown in Table 1. Age (mean, SD) was 72.8 (2.1) years, participation was balanced across sex (50% women), few were current smokers (8.6%), and 12% had a BMI of >30 kg/m2. The overall drop-out due to death, withdrawal, or exclusion was 25% over the course of the study (further information on dropout in Supplementary material online). From Years 1–5, participation at follow-up measurements declined from 1277 (81%) to 1020 (65%), respectively. Clinical and study characteristics from Years 1, 3, and 5 are available in Supplementary material online, Tables S2–S4.. Continuous cardiovascular risk score and individual cardiovascular risk factors The mean CCR, individual cardiovascular risk factor levels, and VO2peak at baseline and Years 1, 3, and 5 are shown in Figure 2A for men and Figure 2B for women, and in Supplementary material online, Table S5 for sexes combined. The main results regarding the effect of ExComb compared to control, and HIIT compared to control and MICT, are shown in Table 2 as the group  time interaction effects from the linear mixed models. Descriptive data on clinical events during follow-up are shown by intervention groups and sex in Table 3. There were no significant between-group differences at Year 5 for CCR. Also, for ExComb vs. control, there were no significant differences at any study year. However, HIIT had lower CCR compared to control at Year 3 (-0.34, 99% CI -0.66 to -0.02) and borderline at Year 5 (-0.32, 99% CI -0.64 to 0.01), and borderline compared to MICT at Year 3 (-0.35, 99% CI -0.72 to 0.02, Table 2 and Supplementary material online, Table S6). For the individual traditional cardiovascular risk factors, there were no significant differences between ExComb vs. control at Year 5, except for resting HR (-1.44 b.p.m., 99% CI -2.67 to -0.21). However, HIIT significantly improved MAP at Year 3 (-1.58 mmHg, 99% CI -3.1 to -0.06), resting HR at Year 5 (1.89 b.p.m, 99% CI -3.42 to -0.36), and BMI at Years 3 (-0.26 kg/m2, 99% CI -0.45 to -0.06) and. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 5 (-0.24 kg/m2, 99% CI -0.44 to -0.04) compared to control. MICT showed similar patterns as control without significant differences. There were no significant group differences for lipid measures, systolic and diastolic BP, waist circumference, and glucose measures (Table 2 and Supplementary material online, Table S6).. Peak oxygen uptake For the total sample, there was practically no change in VO2peak over the 5 years (28.6–28.4 mL/kg/min, 0.7% decline). At Year 5, HIIT had significantly higher VO2peak (mL/kg/min) compared to control (0.76 mL/kg/min, 99% CI 0.02–1.51), but not compared to MICT (0.75 mL/kg/min, 99% CI -0.12 to 1.62). VO2peak scaled to fat-free mass was close to significant at Year 5 for HIIT compared to control (1.0 mL/kg fat-free mass/min, 99% CI -0.02 to 2.02) and MICT (0.96 mL/kg fat-free mass/min, 99% CI -0.23 to 2.15, Table 2), but not for ExComb compared to Control. At Years 1 and 3, both ExComb and HIIT alone had significantly higher VO2peak compared to Control, and for HIIT compared to MICT (all p < 0.01, Table 2). There were no significant between-group differences between MICT and control (Supplementary material online, Table S6).. Results by sex In analyses on effect modification by sex at Year 5, none of the analyses showed significant results. At Year 1, women in HIIT compared to control had a significantly lower effect on waist circumference than men in HIIT (1.8, 99% CI 0.0–3.6, P = 0.009).. Discussion In this large, long-term exercise trial, ExComb did not improve CCR, or individual traditional cardiovascular risk factors, compared to control. Furthermore, although ExComb showed a higher VO2peak at Years 1 and 3 compared to control, the effect estimate was not significant at Year 5. The effect on VO2peak for ExComb was due to a strong and significant effect for HIIT compared to control at all follow-ups, while there was no clear sign of between-group differences on VO2peak for MICT and control. HIIT also showed a significantly lower CCR at Year 3 and near-significant trend at Year 5 compared to control. In general, the results signal an effect on cardiovascular risk reduction of HIIT in older adults mostly mediated through effects on VO2peak, without convincing evidence for other risk factors (Graphical abstract). A healthy and for age relatively fit study sample, contamination between intervention groups, and adherence to exercise intervention (cross-over) between intervention groups have likely challenged the possibility to detect between-group differences.. Continuous cardiovascular risk score and individual risk factors Although none of the group comparisons for CCR were significant at Year 5, the HIIT vs. control comparison was close to significant (-0.32, 99% CI -0.64 to 0.01, P = 0.011) and was significant at Year 3. This suggests that, although the individual risk factors mostly did not show significant between-group differences, the combined distribution of important cardiovascular risk factors was improved with HIIT compared to control. However, it should be noted that there were. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. models were performed, one for the ExComb vs. control comparison, and one for the comparison of HIIT and MICT to control. Participants with missing data on at least one of the follow-up time points are also included in the mixed model analysis and contribute to the estimate at these points, though with less weight at these time points than if complete data on that participant were available. Hence, with a mixed model, no imputation of missing data is needed. The estimates from a mixed model analysis are unbiased as under the missing at random (MAR) assumption, while a complete case analysis would be unbiased only under the more restrictive missing completely at random (MCAR) assumption. We analysed for effect modification by sex by including the two-way interaction between time and sex and the three-way interaction between group, time, and sex. All analyses forming basis for main results were performed by the intention-to-treat principle. In addition, selected perprotocol analyses were performed to investigate the impact of exercise adherence (Supplementary material online). Further information including data on the number of participants and observations included in analyses are shown in Supplementary material online, Table S1. Due to multiple testing, a two-sided P-value of <0.01 was considered statistically significant, and 99% CIs are reported. Statistical analyses were performed using Stata MP 16.0 (StataCorp, College Station, TX, US) and R (www.rproject.org)..

(6) 6. J.M. Letnes et al.. Table 1. Baseline characteristics by sex and intervention group. Characteristic. Men. ........................................................................... Women. .......................................................................... Control. MICT. HIIT. Control. MICT. HIIT. (N 5 379). (N 5 188). (N 5 210). (N 5 401). (N 5 199). (N 5 190). Age (years). 73 (2.0). 73 (2.1). 73 (2.1). 73 (2.1). 73 (2.0). 73 (2.0). Weight (kg) Height (cm). 83 (11) 177 (5.7). 82 (11) 177 (5.9). 84 (12) 177 (6.1). 68 (11) 163 (5.3). 68 (11) 163 (5.0). 68 (11) 163 (5.4). Fat-free mass (kg). 61 (6.3). 61 (6.6). 61 (6.7). 44 (4.4). 44 (4.1). 44 (4.8). Body fat (%) PA adherencea. 26 (6.2) 88 (23%). 25 (6.5) 61 (32%). 26 (6.6) 64 (30%). 35 (7.1) 91 (23%). 34 (7.2) 35 (18%). 35 (6.5) 50 (26%). ..................................................................................................................................................................................................................... 31 (6.8). 32 (6.8). 31 (6.6). 26 (5.0). 26 (5.0). 26 (4.9). 1.1 (0.09) 17.3 (1.4). 1.1 (0.09) 17.2 (1.4). 1.1 (0.09) 17.5 (1.3). 1.1 (0.09) 17.2 (1.6). 1.1 (0.09) 17.1 (1.5). 1.1 (0.09) 17.4 (1.4). Myocardial infarction. 30 (8.2%). 19 (11%). 14 (6.9%). 8 (2.1%). 5 (2.6%). 4 (2.2%). Angina Heart failure. 23 (6.3%) 2 (0.5%). 6 (3.4%) 2 (1.1%). 6 (3.0%) 5 (2.5%). 3 (0.8%) 1 (0.3%). 2 (1.1%) 0 (0%). 2 (1.1%) 0 (0%). Atrial fibrillation. 27 (7.4%). 22 (12%). 20 (10.0%). 9 (2.3%). 8 (4.3%). 4 (2.2%). Stroke COPD. 19 (5.2%) 15 (4.1%). 20 (11%) 11 (6.1%). 8 (4.0%) 8 (4.0%). 12 (3.2%) 16 (4.2%). 8 (4.2%) 13 (6.9%). 9 (5.0%) 7 (3.9%). Asthma. 23 (6.3%). 13 (7.2%). 20 (9.9%). 34 (8.9%). 22 (12%). 17 (9.4%). Cancer Current smoker. 51 (14%) 30 (8.1%). 37 (21%) 20 (11%). 36 (18%) 14 (7.0%). 62 (16%) 33 (8.6%). 29 (16%) 18 (9.5%). 30 (17%) 15 (8.2%). Former smoker. 184 (50%). 86 (48%). 99 (50%). 142 (37%). 79 (42%). 59 (32%). Alcohol, bingeb Alcohol (units/week). 32 (9.1%) 4.7 (4.6). 16 (9.6%) 4.5 (4.2). 16 (8.2%) 4.7 (4.8). 13 (3.6%) 3.2 (3.6). 5 (2.8%) 2.5 (3.3). 6 (3.6%) 2.1 (2.7). Lipid lowering therapy. 30 (7.9%). 17 (9.0%). 17 (8.1%). 35 (8.7%). 15 (7.5%). 25 (13%). 17 (4.5%) 147 (39%). 10 (5.3%) 69 (37%). 17 (8.1%) 64 (30%). 17 (4.2%) 124 (31%). 10 (5.0%) 55 (28%). 10 (5.3%) 60 (32%). 26 (6.9%). 7 (3.7%). 17 (8.1%). 7 (1.7%). 5 (2.5%). 5 (2.6%). 4 (1.9%). 4 (1.0%). 5 (2.5%). 3 (1.6%). Beta blockersc Antihypertensives Antidiabetic medication Nitrates. 2 (0.5%). 0 (0%). Values are mean (standard deviation), or n (%). COPD, chronic obstructive pulmonary disease; HIIT, high-intensity interval training; MICT, moderate-intensity continuous training; PA, physical activity; VO2peak, peak oxygen uptake. a Adherence to PA recommendations prior to study inclusion. b Alcohol intake >5 units per sitting frequently (weekly). c Beta-blockers or heart selective calcium channel blockers.. no significant differences in CVD events or deaths between the intervention groups, as previously reported.15 The descriptive data (Figure 2) showed that the significant effects by HIIT on BMI were mostly mediated through effects in women, with a similar trend for some other risk factors. However, formal testing by including three-way interaction terms did not show significant difference in effect estimates across sex. Still, one might speculate that these trends may stem from men (27%) being more physical activity than women (22%) at baseline. Although this study did not show a clear effect of HIIT, MICT, or their combination (ExComb) on cardiovascular risk factor reduction beside changes in VO2peak when compared to an active control group, these data should not be interpreted as evidence of lack of an effect of exercise on overall health. We want to emphasize that the study did not have a sedentary control group, and effects of exercise for promotion of health and primary prevention are thoroughly established.31. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... We believe several factors may have affected the possibility of detecting significant between-group differences. First, the participants had better self-reported health and higher education were more physically active and reported less cardiovascular and other disease at study start compared to non-participants,16 meaning that participants self-selecting to participation had a favourable cardiovascular risk profile compared to the age-matched general population. The mean BP at baseline was indeed 5 mmHg lower than the average for adults in their 70s in the same area (central Norway),32 and BMI and lipid profile were similarly favourable. Thus, the potential to improve risk factors beyond baseline levels might have been limited (ceiling effect) due to the self-selection of healthy and fit participants into the study. Furthermore, based on self-reported exercise habits, the proportion of control performing high-intensity exercise was higher than MICT at all follow-ups, whereas HIIT performed considerably more high-intensity exercise than the two other groups.15 Still, high-intensity exercise was carried out by substantial portions of. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. VO2peak (mL/kg/min) Respiratory exchange ratio Borg scale peak.

(7) 7. Cardiovascular risk profile of older adults. line), 1, 3, and 5 by the three intervention arms. The combination of HIIT and MICT (ExComb) is not shown. BMI, body mass index; BP, blood pressure; CCR, continuous cardiovascular risk score; FFM, fat-free mass; HbA1c, glycosylated haemoglobin; HIIT, high-intensity interval training; HDL, high-density lipoprotein; LDL, low-density lipoprotein; MAP, mean arterial pressure; MICT, moderate-intensity continuous training group; TG, triglycerides; VO2peak, peak oxygen uptake.. those both in control and MICT,15 and this contamination between intervention groups likely influenced the ability to detect betweengroup differences. Especially, due to these factors, the ‘exercise vs. control’ comparison was blurred. Several previous short-term studies (<1 year) have investigated the effect of aerobic exercise compared to a control group on cardiovascular risk factors in older adults, showing benefits on BP,14,33 resting HR,34 BMI, waist circumference,35 and glucose. .. .. .. .. .. .. .. .. .. .. .. ... homeostasis.36,37 The effect of exercise on lipids in older adults has shown somewhat conflicting results.35,38–40 Importantly, evidence on the contribution of different relative exercise intensities in older adults is almost absent. Results from some randomized clinical trials have shown the effect of high-intensity exercise compared to the moderate-intensity exercise on insulin resistance measures,41,42 somewhat contradictory to our findings of no significant betweengroup differences for glycosylated haemoglobin and glucose. Self-. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. Figure 2 (A) Men and (B) women. Descriptive data presented as means and 99% confidence intervals for each risk factor at study Years 0 (base-.

(8) 8. J.M. Letnes et al.. reported habitual exercise increased in all groups from baseline to Year 1,15 and BP measures decreased in all groups with lack of between-group differences after the first year. MAP was significantly lower for HIIT compared to control at Year 3, but also this effect was attenuated at Year 5. The effect of exercise on lipids in older adults has, as mentioned, shown varied results. Similarly, this trial does not show clear between-group effects for different intensities. This is similar to a 1-year trial randomizing 50–65-yearold sedentary adults to high- and low-intensity training or control, without being able to show between-group differences for lipid. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. measures.43 Large effects of exercise or differential effects of various exercise intensities on lipid levels in older adults is thus not thoroughly established, and factors other than exercise may have a larger relative impact on lipid profiles with higher age. Park et al.44 studied CRF and lipid levels in a cohort of 11 418 men from the Aerobics Center Longitudinal Study and showed how levels of TC, LDL-C, and TG peak around 50 years of age only to decline with higher age, while HDL-C increased steadily. The same study showed that the favourable effect of CRF on lipids weakened with age and was partially gone at high age.44. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. Figure 2 Continued..

(9) 9. Cardiovascular risk profile of older adults. Table 2 Results from linear mixed models showing treatment effect as year 3 group interaction with 99% confidence interval for ExComb, moderate-intensity continuous training, and high-intensity interval training compared to control as well as descriptive mean (standard deviation) for control Risk factor. Year Control,. ExComb vs. control. HIIT vs. control. HIIT vs. MICT. ............................................ ............................................ ............................................. Mean (SD) Estimate (99% CI) P-Value Estimate (99% CI) P-Value Estimate (99% CI) P-Value. .................................................................................................................................................................................................................... 0. 0 (2.98). 1. -0.76 (3.06). -0.08 (-0.32 to 0.17). 0.42. -0.1 (-0.4 to 0.2). 0.38. -0.06 (-0.41 to 0.29). 0.68. 5 HDL cholesterol (mmol/L) 0. 0.1 (2.99) 1.75 (0.51). -0.19 (-0.46 to 0.07). 0.055. -0.32 (-0.64 to 0.01). 0.011. -0.24 (-0.62 to 0.13). 0.095. 1. 1.78 (0.51). 0.01 (-0.02 to 0.04). 0.51. 0.01 (-0.03 to 0.05). 0.53. 5 LDL cholesterol (mmol/L) 0. 1.63 (0.46) 3.42 (0.97). 0.01 (-0.03 to 0.05). 0.43. 0.03 (-0.02 to 0.07). 0.089. 0.04 (-0.02 to 0.09). 1. 3.36 (0.95). -0.03 (-0.12 to 0.07). 0.48. -0.05 (-0.17 to 0.06). 0.24. -0.05 (-0.19 to 0.08). 0.3. 5 0. 3.16 (0.95) 5.68 (1.1). -0.03 (-0.13 to 0.07). 0.46. -0.04 (-0.16 to 0.09). 0.47. -0.01 (-0.16 to 0.13). 0.81. 1. 5.54 (1.08). -0.02 (-0.12 to 0.08). 0.59. -0.03 (-0.16 to 0.09). 0.49. -0.02 (-0.17 to 0.12). 0.67. 5 0. 5.35 (1.13) 1.13 (0.53). -0.05 (-0.16 to 0.07). 0.3. -0.03 (-0.16 to 0.11). 0.64. 0.04 (-0.12 to 0.2). 0.54. 1. 1.01 (0.47). -0.01 (-0.06 to 0.04). 0.64. -0.01 (-0.07 to 0.06). 0.83. 0.01 (-0.07 to 0.08). 0.77. 5 0. 1.1 (0.48) 75.4 (9.77). -0.05 (-0.11 to 0.01). 0.024. -0.06 (-0.13 to 0.01). 0.023. -0.02 (-0.1 to 0.06). 0.45. 1. 73.5 (9.48). -0.09 (-1.13 to 0.95). 0.82. -0.32 (-1.61 to 0.97). 0.52. -0.46 (-1.96 to 1.04). 0.43. 5 0. 76.7 (9.94) 135 (17.5). -0.09 (-1.22 to 1.04). 0.84. -0.47 (-1.87 to 0.93). 0.39. -0.75 (-2.36 to 0.87). 0.23. 1. 132 (17). 0.07 (-1.89 to 2.02). 0.93. 0.25 (-2.18 to 2.68). 0.79. 0.35 (-2.48 to 3.18). 0.75. 5 0. 135 (17) 94.9 (10.5). -0.4 (-2.53 to 1.73). 0.63. -0.12 (-2.76 to 2.52). 0.91. 0.54 (-2.5 to 3.59). 0.65. 1. 92.7 (10.2). -0.04 (-1.21 to 1.13). 0.93. -0.13 (-1.58 to 1.32). 0.82. -0.18 (-1.87 to 1.51). 0.78. 5 Resting heart rate (b.p.m.) 0. 95.8 (10.4) 65.4 (10.9). -0.2 (-1.47 to 1.07). 0.69. -0.35 (-1.93 to 1.23). 0.57. -0.31 (-2.13 to 1.51). 0.66. 1. 64.2 (10.3). -0.44 (-1.59 to 0.7). 0.32. -0.35 (-1.78 to 1.07). 0.52. 0.17 (-1.49 to 1.83). 0.79. 5 Waist circumference (cm) 0. 63.8 (10.7) 94.2 (10.7). -1.44 (-2.67 to -0.21) 0.003. -1.89 (-3.42 to -0.36). 0.002. -0.86 (-2.62 to 0.9). 0.21. 1. 92.1 (11.9). -0.06 (-0.8 to 0.68). 0.82. -0.3 (-1.21 to 0.62). 0.4. -0.46 (-1.52 to 0.6). 0.26. 5 0. 94.8 (10.9) 25.9 (3.42). -0.09 (-0.9 to 0.72). 0.77. -0.47 (-1.47 to 0.53). 0.23. -0.74 (-1.9 to 0.42). 0.099. 1. 25.6 (3.44). -0.14 (-0.29 to 0.01). 0.018. -0.18 (-0.37 to 0). 0.011. -0.09 (-0.3 to 0.13). 0.29. 5 0. 25.7 (3.49) 5.65 (0.39). -0.11 (-0.27 to 0.05). 0.072. -0.24 (-0.44 to -0.04). 0.002. -0.25 (-0.48 to -0.02) 0.005. 1. 5.62 (0.47). -0.03 (-0.07 to 0.02). 0.12. -0.02 (-0.07 to 0.03). 0.34. 0.01 (-0.05 to 0.07). 0.62. 5 0. 5.54 (0.58) 5.65 (0.75). -0.01 (-0.05 to 0.04). 0.76. -0.01 (-0.07 to 0.05). 0.59. -0.01 (-0.08 to 0.05). 0.62. 1. 5.62 (0.91). -0.02 (-0.12 to 0.08). 0.54. -0.04 (-0.16 to 0.09). 0.46. -0.02 (-0.17 to 0.12). 0.67. 5 0. 5.53 (1) 28.6 (6.41). -0.06 (-0.17 to 0.04). 0.13. -0.08 (-0.22 to 0.05). 0.11. -0.04 (-0.19 to 0.12). 0.55. 1. 30.6 (6.87). 0.61 (0.08 to 1.15). 0.003. 1.01 (0.36 to 1.67). <0.001. 5 0. 28.4 (6.65) 41.1 (6.82). 0.39 (-0.22 to 1). 0.097. 0.76 (0.02 to 1.51). 0.008. 1. 43.5 (7.53). 0.76 (0.03 to 1.49). 0.007. 1.32 (0.42 to 2.22). <0.001. 5. 40.8 (7.38). 0.52 (-0.31 to 1.35). 0.11. 1.00 (-0.02 to 2.02). TC (mmol/L). TG (mmol/L). Diastolic BP (mmHg). Systolic BP (mmHg). MAP (mmHg). BMI (kg/m2). HbA1c (%). Glucose (mmol/L). VO2peak (mL/kg/min). VO2peak (mL/kg fat-free mass/min). 0.012. 0 (-0.05 to 0.05). 0.89 0.073. 0.8 (0.04 to 1.57). 0.007. 0.75 (-0.12 to 1.62). 0.027. 1.11 (0.07 to 2.16). 0.006. 0.96 (-0.23 to 2.15). 0.038. BMI, body mass index; BP, blood pressure; CCR, continuous cardiovascular risk score; CI, confidence interval; ExComb, combined exercise groups; HbA1c, glycosylated haemoglobin; HDL, high-density lipoprotein; HIIT, high-intensity interval training; LDL, low-density lipoprotein; MAP, mean arterial pressure; MICT, moderate-intensity continuous training; SD, standard deviation; VO2peak, peak oxygen uptake; TC, total cholesterol; TG, triglycerides.. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. CCR (sum of Z).

(10) 10. J.M. Letnes et al.. Table 3. Clinical events during 5 years of follow-up in men and women by intervention groups. Clinical events. Control. ExComb. MICT. HIIT. ................................... ................................... ................................... ................................... Men. Men. Men. Men. Women. Women. Women. Women. .................................................................................................................................................................................................................... 5.0 (19). 4.5 (18). 5.5 (22). 3.3 (13). 7.4 (14). 4.5 (9). 3.8 (8). CVD. 0.5 (2). 0.2 (1). 1.3 (5). 0.5 (1). 1.5 (3). 0.5 (1). 1.0 (2). 0. Cancer Other. 2.6 (10) 1.8 (7). 3.2 (13) 1.0 (4). 3.2 (13) 1.0 (4). 2.8 (11) 0.5 (1). 4.2 (8) 1.6 (3). 3.5 (7) 0.5 (1). 2.3 (5) 0.5 (1). 2.1 (4) 0. All CVD. 2.1 (4). 21.1 (80). 11.2 (45). 20.9 (83). 9.3 (36). 19.1 (36). 11.1 (22). 22.4 (47). 7.4 (14). Myocardial infarction Cardiac arrest. 4.5 (17) 0.3 (1). 1.7 (7) 0. 4.8 (19) 0.5 (2). 0.5 (2) 0. 2.1 (4) 0. 0.5 (1) 0. 7.1 (15) 1.0 (2). 0.5 (1) 0. Unstable angina. 0.3 (1). 0.2 (1). 0.8 (3). 0.3 (1). 0. 0.5 (1). 1.4 (3). 0. Heart failure Stroke. 1.3 (5) 5.8 (22). 1.2 (5) 2.2 (9). 3.3 (13) 4.0 (16). 1.3 (5) 2.3 (9). 3.2 (6) 4.3 (8). 2.0 (4) 2.5 (5). 3.3 (7) 3.8 (8). 0.5 (1) 2.1 (4). Atrial fibrillation. 6.9 (26). 5.5 (22). 10.1 (40). 4.1 (16). 9.6 (18). 6.0 (12). 10.5 (22). 2.1 (4). Atrial flutter Other tachycardia. 1.6 (6) 2.4 (9). 0.7 (3) 0. 2.8 (11) 1.3 (5). 1.0 (4) 0.8 (3). 2.7 (5) 0.5 (1). 2.0 (4) 1.0 (2). 2.9 (6) 1.9 (4). 0 0.5 (1). PCI. 5.5 (21). 1.7 (7). 5.0 (20). 1.2 (5). 3.7 (7). 1.0 (2). 6.2 (13). 1.6 (3). CABG CVD eventsa. 2.1 (8) 21.4 (81). 1.0 (4) 11.5 (46). 2.5 (10) 21.3 (85). 0.3 (1) 9.5 (37). 2.1 (4) 19.7 (37). 0.5 (1) 11.6 (23). 2.9 (6) 22.9 (48). 0 7.4 (14). All cancers. 14.2 (54). 11.5 (46). 12.1 (48). 11.1 (43). 10.1 (19). 12.1 (24). 13.8 (29). 10.0 (19). 3.2 (12) 0.8 (3). 1.5 (6) 1.2 (5). 3.0 (12) 1.0 (4). 3.3 (13) 0.5 (2). 2.1 (4) 1.1 (2). 4.0 (8) 0.5 (1). 3.8 (8) 1.0 (2). 2.6 (5) 0.5 (1). 1.3 (5). 0. 0.5 (1). 0. 2.1 (4). 11.3 (44). 2.1 (4) 11.7 (22). 12.1 (24). 6.2 (13) 14.3 (30). 10.5 (20). Gastrointestinal Respiratory Breast Prostatic Cancer eventsa. 0 5.3 (20) 15.0 (57). 2.2 (9). 0. 12.1 (50). 4.3 (17) 13.1 (52). Values are % (n). CABG, coronary artery bypass grafting; CVD, cardiovascular disease; ExComb, combined exercise groups; HIIT, high-intensity interval training; MICT, moderate-intensity continuous training; PCI, percutaneous coronary intervention. a Fatal and non-fatal events combined.. Long-term exercise and expected agerelated decline of VO2peak VO2peak increased markedly in all three groups from baseline to Year 1, reflecting changes in exercise habits in all study groups. From Years 1–5 there was a linear decline of 2% per year for all three groups combined, similar to the 20% 10-year longitudinal decline in VO2peak found in adults >70 years both in the Baltimore Longitudinal Study of Aging,7 and the Norwegian HUNT study,45 where the latter is located in the same county as the Generation 100 study. However, due to the significant increase in the first year, VO2peak was higher after 5 years than at baseline in HIIT (þ0.5 mL/kg/min), and only slightly below the baseline value for MICT and control (-0.3 and -0.5 mL/kg/min), which is remarkable given the 10% expected decline over 5 years. In the mentioned HUNT study,45 where the mean age was 50 years at first survey, those reporting high-intensity exercise at both surveys 10 years apart still had a 1% annual decline in VO2peak on average, similar to the 1.1% annual decline found in those performing moderate-intensity exercise on both occasions, supporting that annual declines are similar across different exercise intensities when they are maintained over time. Given that the decline in VO2peak is more pronounced at higher age,7,45 the data from our study are well in line with what is expected based on the mentioned. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ... observational data also for the HIIT group. In HUNT, changing intensity level of leisure-time exercise from moderate-intensity at the first survey to high-intensity exercise at the second survey was associated with a considerably lower decline of 4.1% over 10 years. Therefore, it is important to note that also in the present study those performing high-intensity exercise had higher absolute values than control and MICT, although the per-year annual decline was similar from Years 1 to 5. This implies that, over time, it seems difficult to overcome agerelated declines in VO2peak by exercise, but regular exercise gives higher absolute values to start the decline from. Our observations that VO2peak was higher in ExComb vs. control, and for HIIT compared to MICT and control when scaled to fat-free body mass, are in line with our recent observation when scaling VO2peak directly to body mass,15 as presented here as well. This demonstrates that changes in VO2peak were due to changes in fitness and not in body composition per se. A larger effect of HIIT compared to MICT and control on VO2peak has previously been shown in small randomized clinical trials with relatively short follow-up,46 but also short-term studies are scarce in older adults.10 Thus, these novel long-term results support the use of HIIT for maintaining health, as low VO2peak previously has been established as a strong predictor of dependency,47 and observational studies suggest 15% lower risk of CVD and all-cause mortality per. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. All-cause mortality Causes of death.

(11) 11. Cardiovascular risk profile of older adults. Strengths and limitations The study is based on data from one of the largest randomized clinical trials performed on exercise in older adults, making the data material unique. However, the study also has notable limitations, in addition to the challenges outlined above. First, adherence to the assigned intervention is challenging for all exercise trials, and in our study, only about half of the participants reported exercise in line with their assigned group for participants in MICT and HIIT. Also, allowing the participants to self-select exercise mode outside organized sessions (walking, cycling e.g.) may have affected exercise intensity and matching of exercise volume. Furthermore, although HIIT was feasible in this healthy and fit sample, this may not be true for all older adults, which in general should be kept in mind when translating our findings to different populations and parts of the world. However, as previously reported, 13% had poor self-reported health at baseline, and CVD and cancer were rather prevalent,16 suggesting that significant comorbidities are not necessarily an obstacle to perform highintensity exercise. Loss to follow-up throughout the study introduces the risk of attrition bias, meaning that although analyses were performed by intention-to-treat including all randomized participants, differences in participation rates at follow-up may introduce bias.. Conclusions Randomization to 5 years of exercise with regular supervision in older adults failed to show lowered individual and clustered cardiovascular risk factors or a higher VO2peak for ExComb compared to control. The significantly higher VO2peak for ExComb at Years 1 and 3 was driven by the effect in HIIT, which had a significantly higher VO2peak at all follow-up years compared to control. Although HIIT showed a mostly non-significant trend of a favourable effect compared to control and MICT for CCR and some individual cardiovascular risk factors, the study did not produce conclusive data regarding favourable health effects of high-intensity exercise compared to moderate-intensity exercise. Despite the large study sample, selection bias favouring participation of healthy participants, incomplete adherence to exercise intervention, contamination between study arms, and an active control group challenged the ability to detect between-group differences.. .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. Supplementary material Supplementary material is available at European Heart Journal online.. Acknowledgements We would like to thank the participants of the Generation 100 study for their participation, and all former and present colleagues at the Cardiac Exercise Research Group that have contributed to conduction of the study and collection of data since 2012. We would also like to thank The NeXt Move Core Facility, NTNU, and the Clinical Research Facility at St. Olav Hospital, Trondheim, for excellent assistance during testing. Also, we would like to thank all master and bachelor students who contributed to data collection.. Funding The Liaison Committee for Education, Research and Innovation in Central Norway (grant number2018/42795). The Research Council of Norway (grant number 239875). The K.G. Jebsen Foundation for Medical Research, Norway (grant number09/2011). NTNU. Central Norway Regional Health Authority, St. Olavs Hospital, Trondheim, Norway (grant number11/16186). The National Association for Public Health (grant number 90004100), Norway. Conflict of interest: In the submitted ICMJE form, Dr Wisløff reports being a consultant for PAI Health Norway related to monitoring of physiological variables using wearable technology, not regarded relevant for this study. Thus, the Authors declare that there is no conflict of interest.. Data availability We are not allowed to share individual data from the current trial, but we open for collaboration with researchers worldwide that will get access to analysed data from our university. We have also established a biobank of blood and genetic material that is planned to be shared with researchers worldwide, but individual data must be analysed within our university and cannot be sent abroad.. References 1. World Health Organization. Ageing and Health; 2018. https://www.who.int/newsroom/fact-sheets/detail/ageing-and-health (Last accessed: 24 August 2020). 2. Aspenes ST, Nilsen TIL, Skaug EA et al. Peak oxygen uptake and cardiovascular risk factors in 4631 healthy women and men. Med Sci Sports Exerc 2011;43: 1465–1473. 3. Kuk JL, Saunders TJ, Davidson LE, Ross R. Age-related changes in total and regional fat distribution. Ageing Res Rev 2009;8:339–348. 4. Lloyd-Jones DM, Evans JC, Levy D. Hypertension in adults across the age spectrum. JAMA 2005;294:466–472. 5. Baumgartner RN, Waters DL, Gallagher D, Morley JE, Garry PJ. Predictors of skeletal muscle mass in elderly men and women. Mech Ageing Dev 1999;107: 123–136. 6. Kodama S, Saito K, Tanaka S et al. Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women. JAMA 2009;301:2024–2035. 7. Fleg JL, Morrell CH, Bos AG et al. Accelerated longitudinal decline of aerobic capacity in healthy older adults. Circulation 2005;112:674–682. 8. Blumenthal JA, Emery CF, Madden DJ et al. Effects of exercise training on cardiorespiratory function in men and women 60 years of age. Am J Cardiol 1991;67: 633–639. 9. Molmen HE, Wisloff U, Aamot IL, Stoylen A, Ingul CB. Aerobic interval training compensates age related decline in cardiac function. Scand Cardiovasc J 2012;46: 163–171.. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. one metabolic equivalent task (MET, 3.5 mL/kg/min) higher VO2peak.6 Although an effect estimate of HIIT compared to the control of 0.76 mL/kg/min after 5 years may seem small, moving a population mean implies affecting the distribution of a risk factor such that it may substantially benefit populational health.48 Importantly, the effects on VO2peak and other cardiovascular risk factors pointed in the same direction as the numerically, but not statistically significant, benefit on survival for HIIT observed in the analysis of the main outcome of the Generation 100 study.15 Furthermore, of note is that no CVD events occurred during supervised exercise over the study course, indicating safety of HIIT in older adults.15.

(12) 12. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 30. Twisk J, Bosman L, Hoekstra T, Rijnhart J, Welten M, Heymans M. Different ways to estimate treatment effects in randomised controlled trials. Contemp Clin Trials Commun 2018;10:80–85. 31. Piepoli MF, Hoes AW, Agewall S et al.; ESC Scientific Document Group. 2016 European Guidelines on cardiovascular disease prevention in clinical practice. Eur Heart J 2016;37:2315–2381. 32. Holmen J, Holmen TL, Tverdal A, Holmen OL, Sund ER, Midthjell K. Blood pressure changes during 22-year of follow-up in large general population—the HUNT Study, Norway. BMC Cardiovasc Disord 2016;16:94. 33. Braith RW, Pollock ML, Lowenthal DT, Graves JE, Limacher MC. Moderate- and high-intensity exercise lowers blood pressure in normotensive subjects 60 to 79 years of age. Am J Cardiol 1994;73:1124–1128. 34. Huang G, Shi X, Davis-Brezette JA, Osness WH. Resting heart rate changes after endurance training in older adults: a meta-analysis. Med Sci Sports Exerc 2005;37: 1381–1386. 35. Kuhle CL, Steffen MW, Anderson PJ, Murad MH. Effect of exercise on anthropometric measures and serum lipids in older individuals: a systematic review and meta-analysis. BMJ Open 2014;4:e005283. 36. Davidson LE, Hudson R, Kilpatrick K et al. Effects of exercise modality on insulin resistance and functional limitation in older adults. Arch Intern Med 2009;169: 122–131. 37. Finucane FM, Sharp SJ, Purslow LR et al. The effects of aerobic exercise on metabolic risk, insulin sensitivity and intrahepatic lipid in healthy older people from the Hertfordshire Cohort Study: a randomised controlled trial. Diabetologia 2010;53:624–631. 38. Kelley GA, Kelley KS, Tran ZV. Exercise, lipids, and lipoproteins in older adults: a meta-analysis. Prev Cardiol 2005;8:206–214. 39. Cunningham DA, Rechnitzer PA, Howard JH, Donner AP. Exercise training of men at retirement: a clinical trial. J Gerontol 1987;42:17–23. 40. King AC, Haskell WL, Taylor CB, Kraemer HC, DeBusk RF. Group- vs homebased exercise training in healthy older men and women. JAMA 1991;266: 1535–1542. 41. Coker RH, Hays NP, Williams RH et al. Exercise-induced changes in insulin action and glycogen metabolism in elderly adults. Med Sci Sports Exerc 2006;38: 433–438. 42. DiPietro L, Dziura J, Yeckel CW, Neufer PD. Exercise and improved insulin sensitivity in older women: evidence of the enduring benefits of higher intensity training. J Appl Physiol 2006;100:142–149. 43. King AC, Haskell WL, Young DR, Oka RK, Stefanick ML. Long-term effects of varying intensities and formats of physical activity on participation rates, fitness, and lipoproteins in men and women aged 50 to 65 years. Circulation 1995;91: 2596–2604. 44. Park Y-MM, Sui X, Liu J et al. The effect of cardiorespiratory fitness on agerelated lipids and lipoproteins. J Am Coll Cardiol 2015;65:2091–2100. 45. Letnes JM, Dalen H, Aspenes ST, Salvesen Ø, Wisløff U, Nes BM. Age-related change in peak oxygen uptake and change of cardiovascular risk factors. The HUNT Study. Prog Cardiovasc Dis 2020;63:730–737. 46. Milanovic Z, Sporis G, Weston M. Effectiveness of High-Intensity Interval Training (HIT) and continuous endurance training for VO2max improvements: a systematic review and meta-analysis of controlled trials. Sports Med 2015;45: 1469–1481. 47. Paterson DH, Govindasamy D, Vidmar M, Cunningham DA, Koval JJ. Longitudinal study of determinants of dependence in an elderly population. J Am Geriatr Soc 2004;52:1632–1638. 48. Rose G. Sick individuals and sick populations. Int J Epidemiol 2001;30:427–432.. Downloaded from https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehab721/6422750 by guest on 11 November 2021. 10. Bouaziz W, Malgoyre A, Schmitt E, Lang PO, Vogel T, Kanagaratnam L. Effect of high-intensity interval training and continuous endurance training on peak oxygen uptake among seniors aged 65 or older: a meta-analysis of randomized controlled trials. Int J Clin Pract 2020;74:e13490. 11. Wisløff U, Støylen A, Loennechen JP et al. Superior cardiovascular effect of aerobic interval training versus moderate continuous training in heart failure patients: a randomized study. Circulation 2007;115:3086–3094. 12. Tjønna AE, Lee SJ, Rognmo Ø et al. Aerobic interval training versus continuous moderate exercise as a treatment for the metabolic syndrome: a pilot study. Circulation 2008;118:346–354. 13. Hamer M, Lavoie KL, Bacon SL. Taking up physical activity in later life and healthy ageing: the English longitudinal study of ageing. Br J Sports Med 2014; 48:239–243. 14. Bouaziz W, Vogel T, Schmitt E, Kaltenbach G, Geny B, Lang PO. Health benefits of aerobic training programs in adults aged 70 and over: a systematic review. Arch Gerontol Geriatr 2017;69:110–127. 15. Stensvold D, Viken H, Steinshamn SL et al. Effect of exercise training for five years on all cause mortality in older adults—the Generation 100 study: randomised controlled trial. BMJ 2020;371:m3485. 16. Stensvold D, Viken H, Rognmo Ø et al. A randomised controlled study of the long-term effects of exercise training on mortality in elderly people: study protocol for the Generation 100 study. BMJ Open 2015;5:e007519. 17. Helsedirektoratet. Folkehelse: Fysisk aktivitet: Anbefalninger; 2011. 18. Borg G. Borg’s perceived exertion and pain scales. Hum Kinet 1998. 19. Moholdt TT, Amundsen BH, Rustad LA et al. Aerobic interval training versus continuous moderate exercise after coronary artery bypass surgery: a randomized study of cardiovascular effects and quality of life. Am Heart J 2009;158: 1031–1037. 20. Reitlo LS, Sandbakk SB, Viken H et al. Exercise patterns in older adults instructed to follow moderate- or high-intensity exercise protocol—the Generation 100 study. BMC Geriatr 2018;18:208. 21. Farinatti PTV, Monteiro WD. Walk–run transition in young and older adults: with special reference to the cardio-respiratory responses. Eur J Appl Physiol 2010;109:379–388. 22. Froelicher V, Myers J. Exercise and the Heart, 5th ed. Philadelphia: Saunders Elsevier; 2006. 23. Stensvold D, Bucher Sandbakk S, Viken H et al. Cardiorespiratory reference data in older adults: the Generation 100 study. Med Sci Sports Exerc 2017;49: 2206–2215. 24. Knopfholz J, Disserol CCD, Pierin AJ et al. Validation of the Friedewald formula in patients with metabolic syndrome. Cholesterol 2014;2014:1–5. 25. Alberti KGMM, Eckel RH, Grundy SM et al.; International Association for the Study of Obesity. Harmonizing the metabolic syndrome. Circulation 2009;120: 1640–1645. 26. Eisenmann JC. On the use of a continuous metabolic syndrome score in pediatric research. Cardiovasc Diabetol 2008;7:17. 27. Lamb MJE, Westgate K, Brage S et al. ADDITION-Plus study team. Prospective associations between sedentary time, physical activity, fitness and cardiometabolic risk factors in people with type 2 diabetes. Diabetologia 2016;59:110–120. 28. Park S, Lee S, Kim Y et al. Altered risk for cardiovascular events with changes in the metabolic syndrome status a nationwide population-based study of approximately 10 million persons. Ann Intern Med 2019;171:875–884. 29. Holvoet P, Kritchevsky SB, Tracy RP et al. The metabolic syndrome, circulating oxidized LDL, and risk of myocardial infarction in well-functioning elderly people in the health, aging, and body composition cohort. Diabetes 2004;53: 1068–1073.. J.M. Letnes et al..

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